Using the Same Pan for Everything
You do not want to use a nonstick pan to cook a steak. Just like you don't want to use cast iron to cook tomatoes, the type of pan you decide to use is just as important as the food you put into it. Do a little research about your ingredients before you fire them and make an educated decision from then on.
You're Adding Oil to Your Pasta Water
Some people think that adding olive oil to your pasta water helps your pasta not stick. This is wrong. Even if your grandmother does it, this is just a waste of perfectly good olive oil. You do not need to put anything in a pasta pot except for salt and water.